1. Field of the Invention
The present invention relates to a video display device, and more particularly, to a video display device including an integrated atypical/typical defect compensation circuit capable of compensating for atypical display defects as well as typical display defects.
2. Discussion of the Related Art
Recently, for video display devices, flat display devices, such as a liquid crystal display (LCD), a plasma display panel (PDP), and an organic light emitting diode (OLED) display device, have mainly been used.
Such a video display device is subjected to an inspection process at a manufacture stage in which the manufacture of a display panel has been completed, to inspect display defects possibly existing on the display panel. When the display panel is detected as having display defects, a repair process is carried out to repair defected portions of the display panel. However, there may be display defects that cannot be repaired by the repair process.
Display defects are mainly caused by a deviation in exposure light amount resulting from the overlapped light exposure in a multi-exposure operation of exposure equipment used in a thin film pattern formation process and the aberrations of multi-lenses used in the exposure equipment. The deviation in exposure light amount causes a variation in the width of thin film patterns, thereby resulting in a deviation in parasitic capacity among thin film transistors, a deviation in height among column spacers to maintain a desired cell gap, a deviation in parasitic capacity among signal lines, etc. Such deviations cause a brightness deviation, so that display defects in the form of vertical lines or horizontal lines may be displayed. Meanwhile, in the case of a liquid crystal display device, which needs a backlight unit, there is a tendency to reduce the spacing of a liquid crystal panel from the backlight unit, in order to achieve slimness. In this case, however, the diffusion path of light emitted from the backlight unit is insufficient, so that typical display defects in the form of horizontal lines corresponding to respective positions of a plurality of lamps may be displayed. However, it is difficult or impossible to eliminate such typical display defects, even through an improvement in process techniques. To this end, a method for compensating for the brightness of a typical display defect region through a data compensation method has recently been proposed.
Meanwhile, display defects may be displayed in the form of not only typical display defects as mentioned above, but also irregular display defects, namely, atypical display defects, due to a process defect such as introduction of foreign matter or formation of pinholes. However, conventional compensation circuits used to compensate for typical display defects have a configuration impossible to compensate for atypical display defects. For this reason, a compensation circuit for compensating for atypical display defects should be separately provided. Where a compensation circuit for compensating for atypical display defects and a compensation circuit for compensating for typical display defects are separately developed, it is also necessary to separately develop timing controllers in which the typical and atypical detect compensation circuits are built, respectively. In this case, accordingly, there is a problem of an increase in manufacturing costs. Furthermore, various printed circuit boards (PCBs) should be used for respective timing controllers. As a result, there is a problem in that the management of timing controllers and PCBs is complicated.